Gonna button up my 4.083 gear and quaife install over thanksgiving and realized theres an issue with backlash for the 4.083 ratio...

So I've got a good assortment of side and pinion shims.

FSM 350z 3.5 gears: .0039"-.0059" backlash

FSM for 06 frontier: .0031"-.0051"
But also list .0039"-.0059" depending on what model, but I can't figure out which frontier model had the 4.083 gears. I know its from a king cab, 4 cylinder, manual but unclear in manual.

So I'm gonna shoot for .0045" and call it a day.

 

I have a diff w new seals and bearings, a nismo cover, cusco 1.5rs and 4.08 gears in it I'm selling in the nnj area classified. Need a stock vlsd pumpkin back. Less than 1000k miles on it too. If u read my past posts on this, I had a nightmare with the install. Finally got it done rite with new everything, and now I'm selling the car. Oh well. This diff definately needs a good home. Let me know fellas.

 

This is the best mod you can get for an NA

 

Just got my 4.08 gears and quaife installed today, not a peep of whine or noise.

FWIW I had my backlash set at .0049"

If anyone is looking at doing the gear setup themselves I have a set of slide on and off pinion setup bearings and press plates / tubes for installing the pinion bearings. Shoot me a PM id gladly lend them out with a small deposit.

 

If i was close I would definitely hit that up!!

 

As would I!

 

I don't know which one I love the most the Quaife diff or the 4.08. Great mod, but it's not a night and day difference. I think I still need more hp. Maybe a HKS supercharger or something, turbo is not an option in my country due to the legislation.

 

I disagree to a point. The 4.08 gears makes a very noticeable difference when hammering thru the gears. It's not a I've jumped 50% in engine power difference but it does put the NA gearing right where it should be.

The quaife I'm truly loving because I don't feel it at all, until I go into a corner under heavy throttle. Selling any sports car with an open differential should be grounds for execution.

So far I've driven 550 miles on the 4.08 gears and havnt noticed any drop in gas mileage. This may change when I change the break in lube tonight and can really lay into it.

 

The gears shouldn't hurt your city mpg because you can simply shift sooner to offset. Highway mpg may or may not be affected based on what speed you drive at.

 

Agreed,

I was very surprised that my city mileage hasn't changed a noticable amount (18.9 MPG) and my high mileage (250 miles at 80-85 mph) was still holding (22.5 MPG, from 23.1MPG).

 

That's very cool of you..however mine is already installed.

Are you fishtailing in 2nd and 3rd gear now?

I average 17-18 mpg driving nice. I do have 19" wheels, big tires, etc..of course 4.08 rear end and Quaife as well.

 

How do you get 25-27 mpg in a Z? How big are your wheels? stock or aftermarket exhaust? ECU tuned?

 

I can definitely break the tires loose in 2nd and 3rd but really have to be into the gas. I'm running 18" axis reverbs which are pretty damn light with 275 wide vredstein ultracs in the back.

It's a whole new car for sure.

 

1) Acceleration is great when you get on it. 3rd gear is alive now
2) High RPM on highway sucks
3) MPG went down from 16.7 to 16.2
4) Gears + loud exhaust = SUCKS!
5) Worth it? Yes but only if you do LSD as well.

 

Can anyone elaborate on points 2 and 3 above? I have the stock vlsd. Can't afford to upgrade both gears and LSD(quafe prob) at once..

Figured gears would be better for a "feel it" standpoint.

 

2) you have a larger ratio final drive, your engine will spin approx 16% higher.

3) honestly my gas mileage was unchanged with gear swap, its against logic but I chalk it up to the increased acceleration keeping me out of the gas (18.5 mpg)

It would be wise do gears and diff at same time, otherwise you will need to reshim both times.

 

Just saw this and wanted to point out there IS a break in period. There is NO debate about it!

When brand new gears mesh, there will be metal shavings that come off. This is due to the high friction and wear of the new gears meshing and is perfectly normal. However, during this wear period, the gears are going to generate a LOT of heat! Enough heat to either break down the oil, and will cause the gears to become very brittle. There needs to be a cool down period during initial break in.

If the gears are not allowed to cool down, and the gear oil breaks down, then down the road the gears will undoubtedly fail due to the burnt gear oil. If the oil does not burn (which it will before this happens) then the gears will simply overheat and cause the gears to become too brittle. The gears are heat treated from the factory to very exact specifications, with the outside being very hard (~65 HRC) and the middle of the gears relatively softer (~45 HRC), and if the heat generated from new gears is not allowed to cool, then the entire gear will simply be "re-treated" with enough heat to harden it even more. This will create a uniformly solid gear, that will not take impact very well at all, and will eventually break due to being too brittle.

Improper break in can also cause gears to warp. Again this is due to heat from friction after the oil has broken down. When people say they hear a "whine" or a "moan" from the rear axle, more than likely it is form a warped gear, or non concentric gear.

I know this because I have seen it time after time happen to people that did not follow the break in procedure properly. If you want a proper break in procedure, here is what we recommend:

-Avoid heavy acceleration during the break in process
-Drive the vehicle lightly for the first 15-20 min and stop. Let the differential cool before proceeding.
-Repeat this process for the first 100 miles
-Drive the vehicle at least 500 miles before towing anything
-Change the gear oil after the first 500 miles. This will remove any metal particles and phosphoric coating shed by the gear seat during the gear's initial break in period.


Overheated gear oil will break down. Period. And it will not do its job. This is the main cause of gear failure.

 

Isn't this dependant upon manufacturer or are they all made generally by the same process and materials? That's a broad statement about the inner and outers for heat capacity.

 

Yes manufacturing processes of the gears will vary, but they all rely on the heat treatment of the metal for the gear's strength. Typically import gears will start as a relativity soft metal, and is made into the desired gear shape while it is still soft. After the gear is created, the outer surface is heat treated. Imports usually have a nitrided coating and domestic uses a phosphate, but it varies by manufacturer. Both methods create about the same hardness. Only the outer surface is heat treated, as you go deeper into the metal it is progressively softer. This creates a hard outer surface for the gears to contact, but a soft inner core to allow some bending and force absorption of the gear (less brittle).

All gears will have this treatment, even gears within the transmission. It allows them to last much longer, and take more force during use. Well, I shouldn't say all gears, cause some aftermarket companies fail to create the heat pattern in the gears (which is why some aftermarket companies have teeth break off very easily). This is why the gears need special attention during the high heat they experience during break in.

Gear oil is used to keep the gears from overheating, but once it breaks down its purpose is useless and the heat will destroy the gears

 

I bought the 4.083 gears and the Quaife LSD. The ring gear just drops right on the carrier. I can move the gear in any direction 0.005". The carrier is not centering the gear. It's generally not acceptable for the bolts to hold the gear in place radialy! The carrier needs to do that.
So where did this gear set idea come from originally and where can I find dimensions for the ID of the Froniter ring gear and the 350z original ring gear? I've tried talking to Nissan in the past for other things and they are a huge company that is hard to find the right person to talk to and that is not willing to share technical information.
Can anybody help me figure this out?